"None of the children had ever gone to school, they had never gone to a doctor," Kollar said. "They were kept in complete isolation."
When asked about Jaycee's condition, the undersheriff said, "She is in good health, but living in a backyard for 18 years does take its toll."
"There is nothing to indicate this was anything other than a stranger abduction," Kollar said. "No connection to the family. They literally snatched her off the streets."
Helen Boyer, the Garridos' neighbor for more than 10 years, said she would be completely shocked if it turned out they really were involved with Jaycee's kidnapping.
"There was no girl living next door, as far as I knew," she said.
Boyer said the couple were caregivers to Phillip Garrido's bedridden mother. They would sometimes have three young blonde girls -- friends of the family, she said -- come visit.
"They were real good neighbors," she said. "Real nice people."
Ernie Allen, president of the National Center for Missing and Exploited Children, told ABCNews.com today that while remarkable, the possible discovery of Jaycee reinforces data that shows kidnappers who are not related to the child typically aren't child killers.
"The Jaycee Dugard case is huge," he said. "There are some people who assume that when a child disappears, there is no hope.
"This provides hope," he said, "for so many searching families."
Many children abducted in the same manner as Jaycee do not have such a happy ending.
Though the country rejoiced when Elizabeth Smart was found alive months after the 14-year-old was snatched, many abducted kids are never heard from again.
One of the most famous missing children cases is that of Etan Patz, the Manhattan boy who disappeared while walking to a school bus in Manhattan in 1979. Despite 30 years of investigations and theories, no trace of the boy has been found.
In June, it appeared that a boy who disappeared in 1955 had turned up alive. John Barnes of Michigan was convinced that he was actually Stephen Damman, snatched from his stroller when he was 2 years old and living on Long Island, N.Y.
Stephen Damman's 78-year-old father, Jerry Damman, became hopeful that he was finally being reunited with his son, but DNA tests dashed his dream.
"It's disappointing and it's too bad we had to go through all of this for actually nothing in the end," Damman said after the results of the tests were revealed.
Steven Stayner also was a prominent case of a kidnapped boy. He was a California boy who was snatched at the age of 7 in 1972. Nine years later, he went into a police station after his captor had grabbed another boy.
"I know my first name is Steven," he told police.
Stayner's story later became a television movie.
More recently, in 2007, Shawn Hornbeck, and a second missing boy were found in Kirkwood, Mo., after Hornbeck allegedly had been held prisoner for four years after vanishing from a St. Louis suburb at age 11.